It has been common practice in vehicles to enhance operator comfort by providing adjustment of the vehicle controls with respect to the operator's seat. In some designs the entire control console, which includes the steering wheel and a plurality of control levers, pivots fore and aft at its connection with the vehicle. These designs are usually provided with a mechanical latching mechanism to allow the console a specific number of incremental adjustments. While this has been acceptable, it does present some drawbacks. One problem resides in the number of incremental positionings. The available space and the structural requirements dictate the number of allowable adjustments. Quite often they are not sufficient to accommodate every operator comfortably.
Another problem exists in the latching componentry itself. As previously mentioned, the latching mechanism must be of sufficient structural size to accommodate some fairly heavy loading. Since an operator is virtually always in contact with the steering wheel, he is often leaning on it with considerable weight. This can be compounded if he is operating a vehicle in rough terrain at which time he will hang on to the steering wheel as the vehicle bounces around. At other times an operator may use the steering wheel, as though it were a grab iron, as he enters the vehicle from the ground. In all of these instances, very high loading may be applied to the console, particularly around the latching mechanism. As a result the size of the latching components are often very large and cumbersome. This can lead to added cost in a structure as well as cluttering the appearance of an unenclosed structure. A typical design is disclosed in U.S. Pat. No. 3,737,003, issued to Duane E. Beals et al on June 5, 1973, and is assigned to the assignee of this invention.
Other designs utilize a fluid actuated cylinder in place of a mechanical latching mechanism to provide an infinitely variable number of positions that the console may assume. U.S. Pat. No. 4,209,074, issued to Lyle E. York on June 24, 1980 and assigned to the assignee of the present invention, is one such design. It provides a console head which supports the steering wheel and the control levers, all of which are connected to the base by hydraulic cylinders. This allows the height as well as the fore and aft position of the steering wheel to be adjusted with respect to the base. It also allows the steering wheel to be positioned anywhere between the maximum extended and retracted limits of the hydraulic cylinders by controlling the flow of hydraulic fluid to one of the mounting cylinders which serves as a master cylinder. All other cylinders move in response to the master cylinder. Controlling an arrangement of this type requires fairly sophisticated hydraulic valving and plumbing all of which adds to the expense of the arrangement.
U.S. Pat. No. 4,392,670, issued to Donald L. Schultz on July 12, 1983, discloses a pivoting steering column that utilizes a pre-pressurized gas cylinder to continuously urge the column in one direction and a second cylinder that mechanically locks the position of the column. The actuating mechanism for the locking cylinder utilizes a plurality of cable actuated levers that serve to unlock the second cylinder. This design only provides two positions for the steering column. It employs a fairly extensive unlatching mechanism as well as needing one cylinder to urge the steering column to one position and a second cylinder to lock the steering column in another position.
The present invention is directed to overcoming one or more of the problems as set forth above.